Specimen analysis device

ABSTRACT

A device is provided for separating a biological fluid specimen into liquid and solid constituents for analysis. The illustrated device includes a receptacle for containing a quantity of the specimen in overlying relation to a filter in sheet form supported on a flat surface, and a vacuum source positioned beneath the filter to draw the liquid portion of the specimen through the filter while leaving the solid constituents on the upper surface of the filter for subsequent microscopic analysis.

United States Patent 1 McCormick 1 May 8, 1973 i [75] Inventor:

[22] Filed:

[54] SPECIMEN ANALYSIS DEVICE James B. McCormick, Hinsdale, Ill. [73]Assignee: Pelam lnc., Hinsdale, 111.

Mar. 1, 1971 [21] Appl. No.: 119,729

[52] U.S. Cl. ..210/94, 210/233, 210/406, [51] Int. Cl. ..B01d 35/00[58] Field of Search ..210/25, 94, 233,

[56] References Cited 7 UNITED STATES PATENTS 2,879,207 3/1959 Poitras..210/406 X 2,307,318 1/1943 Kinney ....210/406 X 3,319,792 5/1967 Lederet a]. ..210/406 X 3/1970 Ryan ..210/406 9/1944 Neises ..210/248 PrimaryExaminer--Samih N. Zaharna Att0rneyAnderson, Luedeka, Fitch, Even &Tabin [57] ABSTRACT A device is provided for separating a biologicalfluid specimen into liquid and solid constituents for analysis. Theillustrated device includes a receptacle for containing a quantity ofthe specimen in overlying relation to a filter in sheet form supportedon a flat surface, and a vacuum source positionedbeneath the filter todraw the liquid portion of the specimen through the filter while leavingthe solid constituents on the upper surface of the filter for subsequentmicroscopic analysis.

13 Claims, 9 Drawing Figures Patented May 8, 1973 3,731,806

2 Sheets-Sheei 2 INVENTOR c/AME'S 5 Ma Coe/v/c/z ATTY5.

SPECIMEN ANALYSIS DEVICE The present invention is directed to a devicefor separating a biological fluid specimen such as urine into solid andliquid components for subsequent analy SIS. v v It is desirable tocollect and test fresh urine for biochemical content and sediment.Generally, this involves separating the solid and liquid constituents bycentrifugation, performing numerous chemical tests in which selectedreagents are separately exposed to small portions of the liquid todetermine the presence of al-,

bumin, sugar, protein, etc. in the sample, and placing the sediment, ifany, upon a slide for microscopic examination. A conventionalurinalysis, therefore, is quite time-consuming in that it entailsnumerous steps and involves not only frequent handling of thecentrifuged liquid but the application of the sediment to a slide aswell.

A principal object of the present invention is to provide an improveddevice for separating a fluid sample such as a urine specimen into itssolid and liquid cornponents. Another object of the invention is toprovide a device for separating the solid and liquid components of aurine sample in such a manner as to provide in the process'a slidecontaining a thin film of sediment suita ble for microscopic analysis.

These and other objects of the invention will become apparent withreference to the following detailed description and accompanyingdrawings, in which:

FIGS. 1 and 2 are prespective views of two separable elements of adevice showing various of the features of the present invention;

FIG. 3 is a perspective view of the elements shown in FIGS. 1 and 2 inworking relationship with each other and with a third elementillustrating how the device may be used;

FIG. 4 is a perspective view showing the form in which the solid andliquid constituents of a sample are supported and contained after thedevice has been used in accordance with FIG. 3;

FIG. 5 is an enlarged sectional elevational view taken along line 5-5 ofFIG. 3;

FIG. 6 is an elevational view of a device constituting an alternateembodiment of the invention;

FIG. 7 is an enlarged sectional elevational view taken along line 77 ofFIG. 6;

FIG. 8 is an enlarged fragmentary top plan view of the device of FIG. 6;and

FIG. 9 is a perspective view of a portion of the device of FIG. 6 as itmight appear being prepared for storage or shipment.

Very generally, there is shown in FIGS. 1-5 of the drawings a device 10comprising a substantially flat plate 12 defining a recessed grid 14adjacent its upper surface and having a hollow needle 16 depending fromits lower surface. A passageway 18 extends from the grid 14 to andthrough the needle 16. A filter in the form of a microporous sheet 20overlies the grid 14, and a retainer 22 having upstanding walls whichencircle the grid is positioned on top of the plate 12. The retainer 22is adapted to contain a quantity of the fluid sample above the filtersheet 20.

In a preferred method of using the device, a sample of a liquid such asurine is placed within the cavity defined by the retainer 22 and theneedle 16 is inserted through the puncturable self-sealing closure 24 ofa previously evacuated or vacuumized tube 26. This brings the passageway18 into fluid communication with the interior of the tube 26, causingthe liquid portion of the sample to be drawn through the filter sheet 20into the. tube, from which it can be removed as needed for biochemicalanalysis. Any sediment within the sample, however, is retained on thesurface of the filter sheet 20 where it is available without furthertransfer for microscopic analysis.

More particularly, the plate 12 is preferably formed of a transparentplastic material such as styrene, polypropylene or the like and, in apreferred embodiment, includes a generally rectangular main body portion28 and a tab 30 which projects from one end edge of the body portion 28and is of a lesser width. The body portion 28 approximates in size thestandard microscope slide, i.e., it is approximately three inches inlength by 1 inch in width. The side edges of the tab 30 are providedwith a notch 32 at the juncture of the tab and body, and a groove 34 isprovided in the lower surface of the plate and interconnects the lowerends of the notches 32. the notches 32 and groove 34 define a line ofweakness along which the tab may be fractured or broken away from thebody 28 for reasons which will become apparent shortly.

The grid 14 provides support for the filter sheet 20 while at the sametime providing for movement of the filtered liquid beneath the sheet toand through the passageway 18. While the grid may be defined in variousways, in the illustrated embodiment, it is formed by providing aplurality of parallel V-shaped small passageways or grooves 36 (FIG. 5)in a generally square area of the upper surface of that end of the body28 of the plate 12 which is adjacent the tab 30. The

grooves are closely spaced and are separated by ridges terminating inpeaks 38. The filter sheet 20 rests upon and is supported by the peaksas well as by the rim of the body portion 28 surrounding the grid. Fluidcommunication between the grooves: and throughout the grid 14 isprovided by channels 40 (FIGS. 2 and 4) which extend transversely of thegrooves and interconnect the ends thereof. Thus, liquid passing throughthe filter sheet 20 flows into the grooves 36 and channels 40 of thegrid 14, from which it is free to flow through the passageway 18 and,ultimately, into the evacuated tube 26, as hereinafter described.

While the above-described grid formation has proven to be quitesatisfactory, it would also be possi ble to insert a pre-forrned gridinto a shallow cavity provided in the plate 12, or to roughen thesurface of the plate, as by sandblasting or etching, to provide for thedesired fluid flow beneath the filter sheet 20.

Extending through the tab 30 between its top and bottom surfaces is ahole 42, and secured to the lower surface of the tab is the needle 16.The needle is hollow and its bore 44 defines a portion of the passageway18, as does the hole 42 which is coaxial with the needle bore. Theneedle is of a stiff, rigid construction, is rein forced by a hub 46 atits upper end, and terminates in a sharpened point 48 which defines theoutlet of the passageway 18. It is thus strong enough and sharp enoughto penetrate the sealed closure 24 of the evacuated tube 26. A canal 50(FIGS. 2, 4 and 5) provided in differential the upper surface of theplate 12 extends between the upper end of the hole 42 and the grid 14,thus connecting the grooves 36 and channels 40 of the grid with the boreof the needle 16 and, thus, with the interior of the evacuated tube 26when the needle has penetrated the stopper 24.

Secured to the upper surface of the palte 12 in overlying relation tothe grid 14, the rim of the plate which encircles the grid, and tab 30is the filter sheet 20. The filter sheet rests upon and is supported bythe peaks 38 defined by the ridges between the grooves 36 and is securedby a layer 51 of a suitable permanent adhesive to the rim of the plateand to the tab 30 (FIG. Desirably, the filter sheet is a microporousmembrane of the millipore type and is comprised of cellulose nitrate,cellulose acetate or a mixture thereof. The pores of the membrane aresmall enough to be impervious to the passage of the liquid specimentherethrough solely under the influence of gravity and the liquid canthus be supported above the membrane without leakage through themembrane. However, the pores are of a size which will permit the liquidportion but not the sediment of the specimen to pass through themembrane under the additional influence of the pressure applied to thespecimen when the passageway 18 is placed in communication with the interior of the evacuated tube 26. The sheet is preferably opticallytransparent so that it is capable of forming a part of a microscopicslide through which light will pass during the examination of thesediment retained by the filter.

Disposed above the filter sheet 20 in overlying relation to the rim ofthe plate 12 which surrounds the grid 14, and also in overlying relationto the canal 50 and hole 42 of the plate, is the retainer 22. Theretainer comprises four interconnected upstanding walls 52 and a flange54 extending horizontally from the lower edges thereof. The retainer isso proportioned that when properly positioned upon the upper surface ofthe plate 12, the walls 52 extend upwardly from adjacent the outer edgesof the grid 14 and the flange 54 extends laterally outwardly to theadjacent side edges of the plate 12. At its forward end, the flange iscontoured to the configuration of the tab 30. As thus positioned, thewalls 52, together with the plate 12 and filter sheet 20, define a fluidreservoir 56 above the filter sheet 20 which is adapted to contain aquantity of the liquid specimen, while the flange 54 not only providesan area of contact between the upper surface of the plate (or filtersheet) and the retainer walls 52, but also overlies and seals off theexposed upper end of the hole 42 and the upper portion of the canal 50,thereby sealing these potential openings and preventing air from beingdrawn therethrough in place of the fluid from the reservoir 56, as isintended. In a preferred embodiment, the reservoir is dimensioned so asto enable it to conveniently contain approximately 5 ml. of thespecimen.

To facilitate attachment of the retainer 22 onto the upper surface ofthe plate 12, it is preferably distributed to the user with a layer orcoating 58 of a releasable or contact adhesive applied to the lowersurface of the flange 54 and protected by a suitable backing sheet. Theuser can thus peel the sheet 60 from the flange 54 and place theretainer on the plate in a relatively secure manner. However, thereleasable nature of the adhesive permits the retainer to be removedfrom the plate after the liquid specimen has been drawn out of thereservoir 56 through the filter sheet 20, thereby rendering the plateand filter sheet conveniently usable as a microscope slide.

As an alternative to the adhesive coating 58 referred to above forfacilitating the positioning of the retainer 22 on the plate 12, thelower surface of the flange 54 and the upper surface of the rim of theplate surrounding the grid 14 can be provided with interfitting grooves,and suitable means could also be provided for clamping the flange 52 tothe plate.

The evacuated tube 26 and closure 24 are of the type frequently used inobtaining blood samples. The tube 26 is in the form of a conventionaltest tube and is therefore compatible with other laboratory equipment.It has been previously evacuated prior to delivery to the user, and itsinterior is under a partial vacuum maintained by the closure 24. Theclosure 24 is formed of a soft rubber which can be readily penetrated bythe sharp needle 16, is capable of maintaining a partial vacuum in thetube 26, and seals the opening occupied by the needle when the needle iswithdrawn, thereby maintaining the filtered liquid within the tube andpreventing bacteria or other contaminants from entering the tube.

While the use of a previously evacuated tube 26 having a self-sealingsoft rubber closure 24 is preferred because of the ease with which itcan be used and the economy which it provides, it would be possible inthe alternative to employ a previously evacuated tube having a closureprovided with a valve adapted to be opened upon the insertion of aneedle or other tubular member into the closure. In such an instance,the needle would not have to be capable of puncturing the closure butthe tube would still collect the liquid portion of the specimen. Asstill another alternative, the vacuum source could be a chambercontinuously evacuated by a pump, with the chamber being adapted to beconnected to the needle 16 or other tubular member through a valve, andwith suitable means provided for collecting the liquid portion of thespecimen.

The use of the device 10 can best be described with reference to thesequence illustrated in FIGS. 1-4 of the drawings. Assuming a specimenof urine has been obtained in the usual manner, the user removes a plate12 with needle 16 and filter sheet 20 permanently attached, a retainer22, and an evacuated closed tube 26 from a suitable kit or carton. Thebacking sheet 60 is removed from the lower surface of the flange 54 ofthe retainer (FIG. 1) and the retainer is placed in overlying relationto the filter sheet 20, with side edges of the flange contiguous to theside edge of the plate and with the suitably contoured extension of theflange overlying the tab 30 of the plate, including the canal 50 andhole 42. The adhesive layer 58 maintains the retainer on the plate. Whenso positioned, the walls 52 of the retainer extend upwardly fromadjacent the side edges of the grid 14 and define a reservoir 56 intowhich a quantity such as 5 ml. of the liquid sample is placed. Becauseof the microporous nature of the filter sheet 20 and the adhesiveinterconnection between the flange of the retainer and filter sheet, theliquid specimen will remain in the reservoir and neither pass throughthe filter sheet by gravity nor pass between the flange 54 of theretainer and the filter sheet.

With the capped evacuated tube 26 held in one hand and the assembledplate 12 and filled retainer 22 held in the other, the point 48 of theneedle 16 is placed in contact with the center portion of the topsurface of the closure 24 and is forced through the closure by theapplication of a force, as with the thumb, to the upper surface of theextension of the flange 54 which overlies the tab 30. This brings thebore 44 of the needle 16 and, hence, the hole 42 of the tab 30, thecanal 50 of the plate, and the grooves and channels 36 and 40 of thegrid 14 into communication with the interior of the evacuated tube,creating a pressure differential across the filter sheet and causing theliquid in the reservoir 56 to be drawn through the filter sheet and intothe tube. However, the sediment or solid particles, if any, in thespecimen will not pass through the filter sheet but will accumulate in athin layer on the upper surface thereof, as illustrated in FIG. 4.

After the liquid has passed through the filter sheet, which willgenerally be accomplished in a very short period of time, the needle 16is withdrawn from the closure 24 and, because of the self-sealing natureof the closure, the liquid is thereby encapsulated in a sealed tube andcan be set aside or shipped to an appropriate laboratory for subsequentanalysis. The retainer 22, being only releasably bonded to the plate 22,is then removed from the plate and the tab portion of the plate, towhich the needle 16 is attached, is fractured from the remainder or body28 of the plate along the line of weakness defined by the notches 32 andgroove 34. This leaves the filter sheet 20, containing the sediment,supported on the upper surface of the plate body 28 (FIG. 4) which is ofthe size and shape of a conventional microscope slide, permitting andgreatly facilitating microscopic examination of the sediment.

There is illustrated in FIGS. 6-9 a device 120 which constitutes analternate embodiment of the invention. Referring to these figures, thereis provided a plate 122 which preferably measures 1 inch by 3 inches,the dimensions of a conventional slide used for microscopic examination.Located generally centrally of the plate 122 is an opening 124, andencircling the opening is a raised ring 125 formed by a flange reversedupon itself to provide an upwardly extending inner, generally centralwall 126, a generally flat annular ledge 128, and a depending, generallycylindrical skirt 130. The inner wall 126 and the skirt 130 definetherebetween a generally cylindrical socket 131, the surfaces of whichtaper inwardly slightly toward the ledge 128 to permit the uppercylindrical wall of a base 132, hereinafter described, to be wedged intothe socket with a sufficiently tight fit to provide an essentiallyairtight seal. A taper of 1 has been found to be satisfactory.Preferably, the ring 125 forms an integral part of the plate 122, whichis molded from a suitable plastic. The portions of the plate 122surrounding the ring are strengthened against warping and bending by arib 134 which is provided on the lower surface of the plate and extendslongitudinally thereof adjacent each of its longitudinal side edges.

Secured to the annular ledge 128 of the ring 125, and spanning thecavity defined thereby in vertically spaced relation to the opening 124,is a filter sheet 136. The filter sheet 136 is of the millipore typepreviously referred to and is cemented or welded to the shoulder 128. Inthe embodiment of FIGS. 6-9, the filter sheet is not supported by agrid, as in the embodiment previously described. However, a thin plasticgrid could be secured to the shoulder 128 beneath the filter sheet 136,if desired.

A retainer 138 is also provided and is adapted to be placed in overlyingrelation to the ring and to contain a quantity of fresh urine forpassage through the filter sheet 136 while leaving behind on the uppersur-v face of the filter sheet any residue or sediment in the urine. Theretainer is preferably molded from a plastic such as polyethylene andincludes a genrally cylindrical side wall 141) defining a liquidretaining chamber which is tapered so as to be of slightly greaterdiameter at its lower end than at its upper end.

The lower edge of the side wall 140 of the retainer is offset outwardlyand then downwardly to provide a generally annular, horizontallydisposed shoulder 142 and a depending, generally cylindrical flange 144.The retainer is so proportioned that it will seat with a watertight sealon the ring 125 of the plate 122, with the flange 144 encircling theskirt of the ring and resting upon the peripheral portion of the filtersheet 136 secured to the ledge 128, and with the inner surface of thewall in generally vertical alignment with the innter surface of theinner wall 126 of the ring. In order to insure such a seal, the outersurface of the skirt 130 and the innter surface of the flange 144 arepreferably tapered slightly to permit a wedging action. This can be mosteasily achieved by flaring the skirt and flange outwardly slightly,thereby providing the desired taper to the generally cylindrical socket131 as well. A taper of 1 has been found to be satisfactory.

The upper portion of the side wall 140 of the retainer is flaredoutwardly significantly to provide the upper portion of the retainerwith a lip 146 defining a wide mouth which facilitates the introductionof the fresh urine into the retainer.

It is desirable that a fixed quantity of urine be passed through thefilter sheet 136 so that the amount of sediment per unit volume can bedetermined and compared with known standards, so that a fixed quantityof liquid urine will be available for analysis, and so that the amountof urine placed in the retainer will not exceed the capacity of thevacuumized tube or the ability of the vacuum to withdraw the entireamount of urine from the retainer. Accordingly, the lip 146 of theretainer is provided with a spill-over aperture 148 (FIG. 8) whichassures that the upper level of the liquid in the retainer will not riseabove the lower edge of the lip 146, and thereby assures that thequantity of liquid in the retainer available for passage through thefilter sheet 136 will not exceed a predetermined amount. In a preferredembodiment, this amount is 300. The liquid which spills over from thelip through the aperture 138 is caught in a trap 150 in the form of apocket formed adjacent one side of the lip and side wall 140. Thus, itis not necessary to pre-measure a precise quantity of urine fordeposition into the retainer but merely to fill the retainer untilliquid begins to spill over into the trap 150.

The base 132 is adapted to facilitate the placing of the lower surfaceof the filter sheet 136 into fluid communication with a vacuum sourcesuch as the vacuumized tube previously referred to. The base is alsoadapted to rest on a flat surface and support the plate 122 and retainer138 supported on the plate, as when the two are interconnected and theretainer is filled with a urine specimen.

The base includes a generally cylindrical tubular body 152, the upperedge of which is proportioned so as to enable it to be wedged into thesocket 131 of the plate 122 to provide a vacuum-tight fit, therebypreventing leakage of air adjacent the periphery of the filter sheet andinefficient use of the vacuum. Disposed internally of the body 152 is agenerally funnel-shaped partition 154 which extends downwardly andinwardly from the inner surface of the body wall and terminates in anaxial conduit 156 having a vertically extending bore within which issecured a needle 160. The needle may be secured within the bore of theconduit 156 by any suitable bonding agent such as, for example, apotting resin. The needle terminates short of the lower edge of thetubular body 152 so that when the base is supported on a flat surfacesuch as a table top, the point of the needle is disposed above suchsurface and will not interfere with a stable disposition of the base onthe surface.

As in the previously described embodiment, the needle 158 is adapted topenetrate the closure 24 of a suitably evacuated tube 26 when the tubeand needle are moved in the direction of each other. To guide the base132 and tube 26 during such relative movement, the inner walls of thebody 152 are provided with inwardlyprojecting guide wings 162. In theillustrated embodiment, four such wings spaced circumferentially 90 areprovided, and the space defined by the wings is slightly greater thanthe diameter of either the closure 24 or tube 26. The inner edges of thewings converge slightly from their lower ends toward their upper ends,and the lower ends of the wings are cut at an angle to facilitate theintroduction of the tube 26 into the interior of the body 152. In orderto facilitate gripping of the base for subsequent separation of the baseand tube 26, and for subsequent separation of the device into its threecomponents, the lower portion of the outer surface of the tubular body152 is provided with a plurality of closely spaced, longitudinallyextending ribs 164.

In use, the device 120 is assembled by placing the retainer 138 on topof the plate 122, adnd by placing the plate and retainer on top of thebase 132, these three components of the device 120 being securely heldtogether by virtue of the wedging action previously described. Thedevice is then supported on a flat surface, this being made possible bythe fact that the lower end or point of the needle 160 is recessedupwardly relative to the lower edge of the base.

A freshly passed urine sample is poured into the retainer 138 until thesample begins to overflow into the trap 150. At this point, there willbe a predetermined quantity, e.g., 3 cc. of urine, above the filtersheet 136. The device is then carefully raised and with a previouslyevacuated tube 26 provided with a penetrable closure 24 supported on aflat surface and stabilized with one hand, and with the device 120grasped firmly in the other, the device is forced downwardly relative tothe tube until the needle 160 penetrates the closure, creating apressure differential across the filter sheet and drawing the fluidportion of the specimen through the sheet while leaving any sedimentincluding cells, crystals, and bacteria supported on the sheet. Theliquid portion of the specimn is thus collected in the tube 26 forsubsequent chemical and physical testing.

The device is then separated from the tube 26 and disassembled into itsthree components. The ribs 164 facilitate grasping of the base 132 toaid in such separation and disassembly. The retainer 138 and base 132may then be discarded. A small amount of stain preservative is thenpreferably placed on the filter sheet 136 to preserve all elements ofthe sediment and provide a clear specimen for microscopic examination.The following formula for a stain preservative has been foundpreferable:

Part 1 Crystal violet 0.03gm Ammononium Oxalate 0.05gm No. 600 Polyoxcarbowax 10.00gm Part ll Safranin 0 0.2gm Ethyl alcohol l0.0gm Glyoxal2.0gm

The two parts are mixed togther in ml of water.

The stain preserved sediment slide and sealed tube 26 are then shippedto a laboratory for chemical, physical and microscopic examination. Toprotect the sedie ment supported on the filter sheet 136 during suchshipment, a cap 166 is preferably provided (FIG. 9) which snaps onto thering of the plate 122 in overlying relation to the upper surface of thefilter sheet, with the lower surface of the central portion of the capspaced slightly from the sediment to avoid contact therewith.Altematively, provision may be made for fracturing the plate 122 so asto separate the ring from the remainder of the plate, thereby renderingthe ring of a suitable size for accommodation within an automaticanalysis apparatus. As a still further alternative, provision could bemade for rendering the ring 125 fracturable from the remainder of theplate 122 and adapting it for attachment as a cap to the tube 26 andclosure 24, thereby permitting shipment of the sediment and liquidportions of the specimen together as a unit to provide added assurancethat they will be properly identified during laboratory analysis.

It should be apparent from the above description that devices formed inaccordance with the present invention are suitable for use in theanalysis of a wide range of liquid specimens and that their use is notconfined to the separation of urine into its liquid and solidcomponents. Also, devices formed in accordance with the presentinvention can be employed in various manners to achieve differentdesired results.

For example, devices formed in accordance with the present inventioncould be used to separate bacteria from virus when both are contained ina liquid specimen, or in a specimen previously diluted with liquid, byusing a membrane or filter which will pass the virus but not thebacteria. When the invention is employed to separate bacteria from aliquid specimen, the device employed is preferably gas sterilized, aswith ethylene oxide, prior to use and a cover, such as that indicated bythe numeral 168 in FIG. 6, seals the inlet of the retainer until thedevice is used. Fluid for bacterial analysis, such as a clean catch"urine specimen, would be deposited into the retainer immediately afterthe cap 168 has been removed and is subsequently drawn through themembrane in the manner previously described. The bacteria is retained onthe surface of the membrane and a thin layer of nutrient agar is thenpoured onto the surface of the membrane to a thickness of l or 2millimeters. The nutrient agar supports bacterial growth in anincubator, and colony count or other bacteriologic processes can followincubation.

A device formed in accordance with the present invention can also beeffectively used in connection with the flotation technique forseparating solid but very minute particles from a specimen. For example,in separating parasites or ova from a stool specimen, the retainer of adevice embodying the present invention is filled with a salt solution ofthe proper specific gravity and a small amount of the stool specimen isadded. The parasites and ova, being of a lighter specific gravity, riseto the top of the liquid. If a cap, such as the cap 168, is applied andthe device inverted, the parasites and ova will be immediately beneaththe membrane. If a vacuum is then applied through the membrane, liquidwill be drawn through the membrane and draw the parasites and ovaagainst the membrane where they will be retained for examination afterthe device is disas- 'sembled.

Also, chemical testing could be conducted on a liquid specimen todetermine such characteristics as the pH value of the specimen byplacing a suitable indicator (e. g., a piece of chemically impregnatedpaper) on or adjacent the membrane or within the receiving tube 26.

Various of the features of the invention are set forth in the followingclaims.

What is claimed is:

l. A device for separating a biological fluid specimen such as urineinto liquid and solid constituents for analysis, said device comprising:plate means including a hollow needle portion defining an elongatedpassageway having an inlet at one end and an outlet at its opposite end,said needle portion being adapted to connect said elongated passagewayto a source of vacuum, said plate means including a generally flat lighttransmitting plate portion provided with a grid area spaced laterallyfrom said needle portion, a liquid transporting canal interconnectingsaid grid area and said elongated passageway in said hollow needleportion, a filter in sheet form supported by said grid area, said filtersheet being light transmitting impervious to the passage of thebiological fluid therethrough under the influence of gravity alone butbeing pervious to the passage of the fluid but not solids contained inthe fluid under the influence of a pressure differential created whensaid outlet of said elongated passageway is connected to a vacuumsource, wall means defining a reservoir adapted to contain a quantity ofthe biological fluid specimen in fluid communication with said elongatedpassageway inlet through said filter sheet, said grid area being adaptedto support said filter sheet in generally planar form, and means tofacilitate fracturing of said plate means so as to permit said needleportion to be separated from said grid area and the portion of thefilter sheet overlying said grid area to render the remaining portion ofsaid plate means usable as a slide for the microscopic examination ofsolids which have accumulated on the surface of said filter sheet afterthe outlet of said elongated passageway has been connected in fluidcommunication with a vacuum source and the liquid portion of the samplehas passed through said filter sheet.

2. A device in accordance with claim 1, wherein said wall defining areservoir is proportioned so as to extend upwardly from said plate inencircling relation to said filter sheet.

3. A device in accordance with claim 1, wherein said generally flatplate portion is further provided with a rim encirclinG said grid areato which said filter sheet is attached in overlying relation to saidgrid area, and wherein said wall defining a reservoir is provided with aflange adjacent its lower edge adapted to overlie portions of said rimof said plate.

4. A device in accordance with claim 1, wherein means are provided formaintaining the lower portion of said wall defining a reservoir in apredetermined location relative to said filter sheet.

5. A device in accordance with claim 4, wherein said means comprises areleasable adhesive layer on the lower portion of said wall.

6. A device in accordance with claim 1, wherein means are provided forreleasably securing said wall defining a reservoir in fiuidtightrelation to said plate.

7. A device as defined in claim 1 wherein said plate means includes atabportion of lesser width then said generally flat plate portion, saidhollow needle portion being formed integral with said tab portion anddepending downwardly from the lower surface thereof, and wherein saidmeans to facilitate fracturing of. said plate means comprises a line ofweakness defined between said tab portion and said flat plate portionalong which said tab portion may be broken away from said flat plateportion.

8. A device for separating a biological fluid specimen such as urineinto liquid and solid constituents for analysis, said device comprising:means defining an elongated passageway having an inlet at one end and anoutlet at its opposite end, means at said passageway outlet adapted toconnect said passageway in fluid communication with a source of vacuum,a filter in sheet form disposed adajcent said passageway, said filtersheet being impervious to the passage of the biological fluidtherethrough under the influence of gravity alone but being pervious tothe passage of the fluid but not solids contained in the fluid under theinfluence of a pressure differential created when said outlet of saidpassageway is connected to said vacuum source, wall means defining areservoir adapted to contain only a predetermined quantity of thebiological fluid specimen in fluid communication with said passagewayinlet through said filter sheet, means including an overflow in saidwall means defining a trap in communication with said reservoir forreceiving a limited amount of fluid introduced into said reservoir inexcess of said predetermined quantity, and means for maintaining saidfilter sheet in generally planar form for subsequent microscopicexamination fo the solids which have accumulated on the surface thereofafter the outlet of said passageway has been connected in fluidcommunication with a vacuum source and the liquid portion of the samplehas passed through said filter sheet.

9. .A device in accordance with claim 8, wherein a plate is provided forsupporting said filter sheet in planar relation, said plate beingprovided with an open ing and with an upstanding ring encircling saidopening, said filter sheet being secured to the upper edge of said ringin overlying relation to said opening, and wherein said wall defining areservoir includes a flange adapted to encircle said ring and be wedgedinto tight fitting, fluid-tight contact with the outer surface thereof.

10. A device in accordance with claim 8, wherein a plate is provided forsupporting said filter sheet in planar relation, wherein said plate isprovided with an opening defining a portion of said elongatedpassageway, wherein said filter sheet overlies said opening and is incommunication therewith, and wherein said means adapted to connect saidpassageway in fluid communication with a source of vacuum is adapted totbe releasably secured to said plate in fluid-tight relation and influid communication with said passageway.

11. A device in accordance with claim 10, wherein said plate defines asocket, and wherein said means adapted to connect said passageway influid communication with a source of vacuum includes a portion adaptedto be received in said socket.

12. A device in accordance with claim 8, wherein said means at saidpassageway outlet adapted to connect said passageway in fluidcommunication with a source of vacuum includes an elongated hollowneedle terminating at said passageway outlet and adapted to penetratethe stopper of a tube previously evacuated to provide a partial vacuumtherein, said means at said passageway outlet further including meansextending generally parallel to said needle for engaging the outerperipheral surface of the previously evacuated tube to provide guidanceas the tube and needle are moved relative to each other incident to thepenetration of the stopper of the tube by said needle.

13. A device in accordance with claim 12, wherein means are provided forsupporting said means at said passageway outlet adapted to connect saidpassageway in fluid communication with a source of vacuum on a flatsurface with the needle depending generally vertically downwardly andwith the point of the needle adjacent to, but spaced from, the flatsurface.

UNITED STATES PATENT OFFICE Q CERTIFICATE OF CORRECTION Patent No.3,731,806 Dated May 8, 1973 In e t James B. McCormick h It is certifiedthat error appears in the above-identified patent .and that said LettersPatent are hereby corrected as shown below:

In Column 3, line 65, "backing sheet" should be followed with In Column7, line 14, "bore" should be fcjzllowed with -'-l58- In Coluinn 10,"line 42, Claim 8, "said passageway" should be followed with inlet Signedand'sealed this 27th day of'November 1973.

LSEAL) Attest:

WARDMe l#E1?HER REN M B YER AhteStihg Offlti At ting Chmmisioher BfPatehts File 30293 "OHM FO-1050 (10-69)

1. A device for separating a biological fluid specimen such as urineinto liquid and solid constituents for analysis, said device comprising:plate means including a hollow needle portion defining an elongatedpassageway having an inlet at one end and an outlet at its opposite end,said needle portion being adapted to connect said elongated passagewayto a source of vacuum, said plate means including a generally flat lighttransmitting plate portion provided with a grid area spaced laterallyfrom said needle portion, a liquid transporting canal interconnectingsaid grid area and said elongated passageway in said hollow needleportion, a filter in sheet form supported by said grid area, said filtersheet being light transmitting impervious to the passage of thebiological fluid therethrough under the influence of gravity alone butbeing pervious to the passage of the fluid but not solids contained inthe fluid under the influence of a pressure differential created whensaid outlet of said elongated passageway is connected to a vacuumsource, wall means defining a reservoir adapted to contain a quantity ofthe biological fluid specimen in fluid communication with said elongatedpassageway inlet through said filter sheet, said grid area being adaptedto support said filter sheet in generally planar form, and means tofacilitate fracturing of said plate means so as to permit said needleportion to be separated from said grid area and the portion of thefilter sheet overlying said grid area to render the remaining portion ofsaid plate means usable as a slide for the microscopic examination ofsolids which have accumulated on the surface of said filter sheet afterthe outlet of said elongated passageway has been connected in fluidcommunication with a vacuum source and the liquid portion of the samplehas passed through said filter sheet.
 2. A device in accordance withclaim 1, wherein said wall defining a reservoir is proportioned so as toextend upwardly from said plate in encircling relation to said filtersheet.
 3. A device in accordance with claim 1, wherein said generallyFlat plate portion is further provided with a rim encirclinG said gridarea to which said filter sheet is attached in overlying relation tosaid grid area, and wherein said wall defining a reservoir is providedwith a flange adjacent its lower edge adapted to overlie portions ofsaid rim of said plate.
 4. A device in accordance with claim 1, whereinmeans are provided for maintaining the lower portion of said walldefining a reservoir in a predetermined location relative to said filtersheet.
 5. A device in accordance with claim 4, wherein said meanscomprises a releasable adhesive layer on the lower portion of said wall.6. A device in accordance with claim 1, wherein means are provided forreleasably securing said wall defining a reservoir in fluidtightrelation to said plate.
 7. A device as defined in claim 1 wherein saidplate means includes a tab portion of lesser width then said generallyflat plate portion, said hollow needle portion being formed integralwith said tab portion and depending downwardly from the lower surfacethereof, and wherein said means to facilitate fracturing of said platemeans comprises a line of weakness defined between said tab portion andsaid flat plate portion along which said tab portion may be broken awayfrom said flat plate portion.
 8. A device for separating a biologicalfluid specimen such as urine into liquid and solid constituents foranalysis, said device comprising: means defining an elongated passagewayhaving an inlet at one end and an outlet at its opposite end, means atsaid passageway outlet adapted to connect said passageway in fluidcommunication with a source of vacuum, a filter in sheet form disposedadajcent said passageway, said filter sheet being impervious to thepassage of the biological fluid therethrough under the influence ofgravity alone but being pervious to the passage of the fluid but notsolids contained in the fluid under the influence of a pressuredifferential created when said outlet of said passageway is connected tosaid vacuum source, wall means defining a reservoir adapted to containonly a predetermined quantity of the biological fluid specimen in fluidcommunication with said passageway inlet through said filter sheet,means including an overflow in said wall means defining a trap incommunication with said reservoir for receiving a limited amount offluid introduced into said reservoir in excess of said predeterminedquantity, and means for maintaining said filter sheet in generallyplanar form for subsequent microscopic examination fo the solids whichhave accumulated on the surface thereof after the outlet of saidpassageway has been connected in fluid communication with a vacuumsource and the liquid portion of the sample has passed through saidfilter sheet.
 9. A device in accordance with claim 8, wherein a plate isprovided for supporting said filter sheet in planar relation, said platebeing provided with an opening and with an upstanding ring encirclingsaid opening, said filter sheet being secured to the upper edge of saidring in overlying relation to said opening, and wherein said walldefining a reservoir includes a flange adapted to encircle said ring andbe wedged into tight fitting, fluid-tight contact with the outer surfacethereof.
 10. A device in accordance with claim 8, wherein a plate isprovided for supporting said filter sheet in planar relation, whereinsaid plate is provided with an opening defining a portion of saidelongated passageway, wherein said filter sheet overlies said openingand is in communication therewith, and wherein said means adapted toconnect said passageway in fluid communication with a source of vacuumis adapted to tbe releasably secured to said plate in fluid-tightrelation and in fluid communication with said passageway.
 11. A devicein accordance with claim 10, wherein said plate defines a socket, andwherein said means adapted to connect said passageway in fluidcommunication with a source of vacuum includes a portioN adapted to bereceived in said socket.
 12. A device in accordance with claim 8,wherein said means at said passageway outlet adapted to connect saidpassageway in fluid communication with a source of vacuum includes anelongated hollow needle terminating at said passageway outlet andadapted to penetrate the stopper of a tube previously evacuated toprovide a partial vacuum therein, said means at said passageway outletfurther including means extending generally parallel to said needle forengaging the outer peripheral surface of the previously evacuated tubeto provide guidance as the tube and needle are moved relative to eachother incident to the penetration of the stopper of the tube by saidneedle.
 13. A device in accordance with claim 12, wherein means areprovided for supporting said means at said passageway outlet adapted toconnect said passageway in fluid communication with a source of vacuumon a flat surface with the needle depending generally verticallydownwardly and with the point of the needle adjacent to, but spacedfrom, the flat surface.